1. Field of the Invention
The present invention relates to a network AV system, and more specifically, to a network AV system including a server and a client connected to the server through a network.
2. Description of the Related Art
A moving picture reproducing device such as a DVD (Digital Versatile Disc) player is capable of special reproducing such as fast-forward reproducing to reproduce a moving picture while fast-forwarding it, reverse-reproducing to reproduce a moving picture while reversing it. When moving picture data in a DVD is compressed by MPEG2, the moving picture data Vm consists of a plurality of frames as shown in FIG. 16. The plurality of frames can be divided into three kinds (I picture, B picture, and P picture) depending on how they are compressed. For fast-forward reproducing, for example, the DVD player extracts frames of I picture among the plurality of frames for reproducing.
Recently, network AV systems using a client-server system have been provided. WO 03/102919 discloses a network AV system having a server including a database that stores a plurality of pieces of moving picture data and a client connected to the server through a LAN (Local Area Network). The client requests the server to provide desired moving picture data, and the server distributes the requested moving picture data to the client in response. The client reproduces the moving picture based on the moving picture data distributed from the server. In the network AV system, the moving picture data is all stored in the server, and therefore the client does not have a hard disk for storing moving picture data. The client simply needs a minimum necessary memory for temporarily storing moving picture data distributed from the server. The network AV system of this kind is desirably capable of fast-forward reproducing and reverse-reproducing.
Japanese Patent Laid-Open No. 2003-111048 discloses a method of allowing the network AV system to carry out special reproducing such as fast-forward reproducing and reverse-reproducing. According to the disclosure of Japanese Patent Laid-Open No. 2003-111048, the client stores information related to moving picture data (information such as the array positions of the plurality of frames constituting the moving picture data) stored in the server. The client specifies a frame to be reproduced based on the information related to the moving picture data and requests the server to distribute the specified frame. In this case, the client needs a memory to store information related to the moving picture data, and therefore the memory capacity of the client cannot be reduced.